Gas fueled pilot burner having a bimetallic primary air valve



P 1953 c; F JENKINS ,5

GAS FuELEb P'ILOT BURNER HAVING A BIMETALLIC PRIMARY AIR VALVE FiledJan. 19, 1948 Snventor GEO/7615 E JEN/ 1M5 Patented Sept. 15, 1953 I GASFUELED PILOT BURNER HAVING A BIMETALLIC PRIMARY AIR VALVE George F.Jenkins, Minneapolis, Minn, assignor to Minneapolis-Honeywell RegulatorCompany, Minneapolis, Minn., a corporation of Delaware ApplicationJanuary 19, 1948, Serial No. 3,029

4 Claims. (01. 158-118) This invention relates to gas burners and, moreparticularly, to gas burners of the type used to serve as a pilot lightfor a larger gas burner and to heat a thermoelectric generator in anarrangement similar to that shown in Ray Patent Number 2,297,718.

Burners of this type usually provide spaced fuel mixture is made toorich, a thermocouple element becomes covered with soot, whichdrastically cuts down on the output of the thermocouple. While themanual adjusting means usually provided on burners of this type, forregulating the primary air entering the burner, are generallysatisfactory for giving the proper mixture at any particular ambient airtemperature, the adjustments do not provide for variation in the mass ofair entering the burner due to changes in the density of the air,resulting from changes in the air temperature. Due to the fact that theambient air temperature adjacent a furnace varies over a wide range, ithas been the practice in burner installations of this type, to adjustthe air inlet to the burner to provide a much richer fuel mixture thanis desirable for heating the thermopile, so as to prevent the burnerfrom going out. This has caused rapid deterioration of the thermocoupleelements with consequent improper operation of controls energizedthereby.

It is the general object of this invention to provide a burner whichovercomes the above mentioned difficulties.

A more specific object of the invention is to provide a burner havingmeans thereon to regulate the flow of primary air into the burner inresponse to changes in ambient air temperature.

Another object of the invention is to provide a fuel burner having amanually adjustable main air opening and an automatically adjustableauxiliary air opening therein for varying the flow of primary air intothe burner.

A further object of the invention is to provide an inexpensive burnerthat maintains a uniform fuel-air ratio in an atmosphere having varyingair temperature.

Other objects of the invention will become apparent upon reading thefollowing detailed description of the invention in conjunction with theaccompanying drawing wherein:

Figure 1 is an elevational view of the burner of this invention showingparts thereof broken away; and

Figure 2 is a cross sectional view of the burner taken on line 22 ofFigure 1.

The burner comprises a main body portion generally designated by thenumeral it. This body portion consists of a hexagonal portion M, anannular extension [2 at the lower or inner end thereof, a reducedannular portion 13 adjacent the upper or outer end of the hexagonalportion, and a longer and still further reduced annular portion I 4beyond the annular portion 13. This particular body construction enablesthe burner to be mounted in an adjustable bracket for supporting theburner in proper relationship with a thermoelectric generator(thermopile), not shown herein but illustrated in a copendingapplication of Charles E. Bodey, Serial Number 787,665, filed November24, 1947, and now matured into Patent No. 2,605,296. Suitably mounted.on'the upper or outer end of the portion It is a burner head l5, thedetails of which form no part of this invention.

A threaded axial bore [6 extends inwardly from the inner or lower end ofthe burner body. This bore tapers down at I! to the lower end of passageIB which extends from said bore to the upper or outer end of the burnerbody. The adjacent portions of said bores l6 and I3 serve as a mixingchamber for gas and air.

A main primary air opening [9 is formed in one of the side walls of theportion H of the burner body. Cooperating with this hole It, to regulatethe rate of air flow therethrough, is a burner nozzle 20.

The burner nozzle has a jet portion 2! of smaller diameter than the borel6, and a large and threaded portion 22 of the same diameter as bore It,a nut-like enlargement 23 extending below the portion 22, and a reducedand exterlorly threaded portion 24 extending below the portion 23. Thenozzle portion 22 is so related to the opening i9 that inward andoutwardadjustment thereof varies the effective size of the opening ill toregulate the quantity of air that will flow .therethrough due to theaspirating effect of the nozzle. The threaded portion 24 is adapted tobe connected to a gas supply conduit, not shown.

A second or auxiliary air opening 25 is provided in another wall of thehexagonal portion II to provide additional air flow to the burner undercertain conditions to be described hereinafter.

Cooperating with this air opening 25, is a bimetallic valve member 26having a flat portion 27 adapted to fit against the side of the portionI I of the body to cover the opening 25, an arcuateportion 28, anenlarged and centrally apertured portion 29 (Figure 2), and a portion 30bent at right angles to the portion 29 so as to lie against a hexagonalsurface diametrically opposite the: bimetallic portion 21. The portion29 of the bimetallic member fits around the extension [2 of the burnerbody and is held thereon by means of a bead |2a formed by swaging thelower end of the portion i2. The bimetal valve 26 is adjusted so as tobe flat against the mouth of opening 25 at the coldest operating airtemperature of the furnace.

Operation The burner, when mounted in its proper relationship with amain burner and thermopile, is placed into operation by connecting theportion 24 to a suitable source of fuel and igniting the fuel and airmixture passing through the burner tip [5. The elements of the burnerwill have the positions shown in Figure 1 of the drawing when theambient air temperature in the furnace is at its coldest operatingcondition. As the temperature of the air surrounding the burnerincreases, due either to external causes or to the heat generated by thefurnace, the bimetallic valve member 26 will move portion 21 thereofaway from opening 25 to permit more and more of the less dense air toenter the burner to maintain the mass ratio of air to fuel substantiallyconstant. As indicated above, the initial fuel air ratio is determinedby the relative position of the nozzle 20 with respect to the burnerbody I or, more exactly, the relative position of the upper end of thethreaded portion 22 of the nozzle with respect to the opening IS in thebody of the burner.

As various modifications of the burner of this invention will becomeobvious to those skilled in the art without departing from the spirit ofthe invention, such as one having an entirely fiat bimetallic valvemember screwed to a burner body, it is to be expressly understood thatthe scope of the invention is to be determined solely by the appendedclaims.

I claim as my invention:

1. A burner comprising a hollow body, an orifice member within saidbody, a first air opening in a wall of said body, said orifice memberhaving an enlarged diameter portion adjustable with respect to saidopening to determine the flow of air therethrough, a second air openingin said wall of said body and spaced from said enlarged diameterportion, and a temperature responsive member having a portion forcovering said second air opening and a portion engaging said body forretaining it on said body, said temperature responsive means beingresponsive to the temperature of the air flowing over it and adjusted toclose only said second air opening at a predetermined low ambientoperating air temperature.

2. A burner comprising a hollow body, a jet member within said body andhaving a threaded enlarged diameter portion; a first air opening in awall of said body arranged to cooperate with said portion of said jetmember to adjust the flow of air therethrough; a second air openingformed in said wall adjacent the upper end of said jet member; and abimetallic member having a fiat portion for covering said second airopening and a washer-shaped portion surrounding said body and anintermediate arched portion, means on said body engaging saidwashershaped portion for retaining said bimetallic member on said body,said bimetallic member being so constructed and adjusted that the fiatportion bears against the body to seal the second opening at the lowestair temperature adjacent the burner air inlet and withdraws from the airopening at higher temperatures.

3. A burner comprising a hollow body, a jet member within said body,said member having a relatively large threaded portion adjacent an endjet portion, a first air opening in a wall of said body and arranged tocooperate with said threaded portion so that the end of said threadedportion adjacent said jet portion adjusts the flow of air therethrough,a second smaller air opening formed in said wall adjacent said jetmember and spaced from said threaded portion, and a bimetallic memberhaving a flat portion for covering said second air opening at the lowestair temperature adjacent the burner air inlet and for withdrawing fromthe air opening at higher temperatures and a washer-shaped portionsurrounding said body and arranged to cooperate with said body to holdsaid member on said body.

4. A burner comprising a hollow body, a jet member within said bodyhaving an enlarged portion adjacent a jet portion, a first air openingin a wall of said body arranged to cooperate with said enlarged portionso that said enlarged portion may be adjusted to control the flow of airtherethrough, a second air opening formed in said wall adjacent theupper end of said jet member, said body having a fiat surface around theouter end of said second air opening, and a bimetallic member having afiat portion for engaging said flat surfaces and covering said secondair opening and a washer-shaped portion surrounding said body, saidwasher-shaped portion having an extension shaped to bear against saidflat surface of said body to prevent rotation of said member about saidbody and arranged to cooperate with said body to hold said member onsaid body.

GEORGE F. JENKINS.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 703,625 Treen July 1, 1902 1,313,694 Hunter Aug. 19, 19191,472,554 Cox Oct. 30, 1923 1,870,253 Johnson Aug. 9, 1932 2,191,178McCollum Feb. 20, 1940 2,263,999 McCollum Nov. 25, 1941 2,296,792 KesterSept. 22, 1942 2,364,299 Kester Dec. 5, 1944 2,379,854 Harper July 10,1945 2,450,790 Greaves Oct. 5, 1948 FOREIGN PATENTS Number Country Date661,612 France Mar. 11, 1929 815,408 France Apr. 12, 1937

